An Extra Second Before New Year

Timekeepers at the Royal Observatory of Greenwich will be adding a "leap second" of time to the clock on Wednesday, a method used sporadically over the past 30 years to offset the fractional slowing of the Earth's rotation.

The extra second will be squeezed in on Dec. 31 after 6:59:59 p.m. and before 7 p.m. ET. Combined with the extra day on Feb. 29, the extra second will make 2008 the longest year since 1992.